Lubricating device for radial sealing strips of inner-axial rotary piston engines of trochoidal construction with sliding engagement

ABSTRACT

This invention relates to a lubricating device for radial sealing strips of an inner-axial rotary piston engine of trochoidal construction with sliding engagement comprising lubricant groove means in the two side walls of sealing strip beds guiding said radial sealing strips, line means, having nonreturn valve means therein, connecting said oil groove means with lubricant pump means, and means controlling said lubricant pump means in accordance with the position of the engine eccentric shaft.

I United States Patent 11 1 1111 3,885,897 Hui L. 1 May 27, 1975 [54] LUBRICATING DEVICE FOR RADIAL 3,178,103 4/1965 Schwacke 418/88 X SEALING STRIPS 0F INNER-AXIAL x323 g z ey we ROTARY PISTON ENGINES OF 3,410,254 11/1968 Huf l23/8.4S TROCHOIDAL CONSTRUCTION WITH 3,514,236 5/1970 Rashev 418/61 B SLIDING ENGAGEMENT 3,583,371 6/1971 King 413/83 X i [75] inventor: Franz Hllf, COIISIaHCE, Germany FOREIGN PATENTS 0R APPLCATIONS [73] Assignee: Dornier System GmbH, 1,905,526 8/l970 Germany 4|8/61 B Friedrichshafen, Germany [22] Filed; Ju|y 16, 97 Primary Examiner-C. J. Husar Assistant ExaminerLeonard Smith [21] APPL N04 379,60] Attorney, Agent, or Firm-James E. Bryan [30] Foreign Application Priority Data [57] ABSTRACT 1972 Germany 2240100 This invention relates to a lubricating device for radial [52] U S 4l8/88 418/97, 418/129 sealing strips of an inner-axial rotary piston engine of g trochoidal construction with sliding engagement com- [5 l] Int. Cl. F04c 29/02 risin lubricant move means in the two side walls of 581 Field 6: Search 418/54, 56, 58, 60, 61 B, P g g 418/88 125 129 97 248 270 sealing strip beds gu1dmg said rad1a1 sealing strips, line means, having non-return valve means therein, con- [56] References Cited necting said oil groove means with lubricant pump means, and means controlling said lubricant pump UNITED STATES PATENTS means in accordance with the position of the engine 298,952 5/I884 Donkin 418/58 eccentric shaft 1,887,884 11/1932 Eyston 413/58 X 1 l,912,845 6/1933 Jaworowski 418/248 X 10 Claims, 10 Drawing Figures PATENTEBrmev I975 SHEET v QM m Qk

SHEET PATHHEBHAYE? 1975 3.885897 sum 6 LUBRICATING DEVICE FOR RADIAL SEALING STRIPS OF INNER-AXIAL ROTARY PISTON ENGINES OF TROCHOIDAL CONSTRUCTION WITH SLIDING ENGAGEMENT The present invention relates to a lubricating device for the radial sealing strips of inner-axial rotary piston engines of trochoidal construction with sliding engagement.

In the heretofore known forms of construction of the radial sealing strips in rotary piston engines of the type referred to above, the sealing strips were positioned more or less loosely in their sealing strip beds in the housing. The sealing strips were moreover unlubricated and dry, which did not lead to the most favorable oper ating conditions, and which affected both the gas sealing and the wear and tear of the sealing strip material. A lubricant supply into the sealing strip bed alone is unsatisfactory because it is primarily the round surface of the sealing strip which is to have a closed lubricating film within its contact range, being dependent on the pivot angle, with the piston sliding past. This is not assured with a general lubricant supply into the sealing strip bed.

It is the object of the present invention to eliminate the disadvantages and drawbacks referred to hereinabove in rotary piston engines and to effect a lubrication of the radial sealing strips which is fully satisfactory in operation.

This object is obtained, in accordance with the present invention, by virtue of the fact that oil grooves are positioned in the two lateral walls of the sealing strip beds guiding the radial sealing strips, which grooves are connected by way of lines equipped with non-return valves with a lubricant pump which is controlled by the rotary position of the eccentric shaft. As a result, an exact dosage or metering of the lubricant is possible since the quantity delivered is regulated by a corresponding setting of the pump. Produced in this manner on the dome of the sealing strips is a continuous lubricating film which, due to the relative pivoting movements between the radial sealing strip and the piston surface, is in sliding contact between sealing strip and piston. Thus, a good sealing effect is achieved at the point of contact, and furthermore, wear and tear of the sealing strip at the dome surface thereof is effectively eliminated.

According to another embodiment of the present invention it is possible to variably dose or meter the amount of lubricant on the two sides of the radial scaling strip bed. In this case, the supply of lubricant is advantageously dosed or metered greater on the rising or running-up side of the radial sealing strip than on the descending or running-down side thereof. The supply, or delivery, of the lubricant may take place simultaneously both at the running-up and at the runningdown side of the sealing strip, but it is advantageous that the supply be effected alternately on one side and then on the other side of the radial sealing strip. It is further possible to supply all of the radial sealing strips with the lubricant at the same time, or to feed the dosed or metered amount of lubricant successively to the in dividual radial sealing strips. This provision is particularly advantageous when other parts necessary for the operation of the rotary piston engine can be used for the lubrication. This is the case, for example, in rotary piston engines which obtain their rotational movement not by the customary toothed wheel gearing, but by an eccentric control with guides or sliding bars.

According to a further embodiment of the present invention, each of the two mutually oppositelypositioned ends of each a sliding bar or linkage may be utilized as the piston of such a lubricant pump. In this case, one of the two thus formed lubricant pumps is advantageously connected with the oil grooves of the running-up side of the radial sealing strips, and the other lubricant pump is connected with the oil grooves of the running-down side of the radial sealing strips.

One embodiment of the present invention is further described hereinafter with reference to the accompanying drawings, wherein FIG. 1 schematically illustrates a two-chambered rotary piston engine with the basic provision of the lubricating device and the arrangement of the lubrication lines or piping;

FIGS. 2a and 2b illustrate the radial sealing strip arrangement on an enlarged scale;

FIG. 3 illustrates one construction of a lubricant pump;

FIG. 4 illustrates a modified embodiment of FIG. 3;

FIGS. 50 and 5b are cross-sectional views taken along line A-A and line A-B-CD-E-A, respectively, of FIG.

FIG. 5c is a cross-sectional view taken along line A-A of FIG. 1 after the rotation of the piston through an angle of FIG. 6a is a cross-sectional view taken along line F-F of FIG. I; and

FIG. 6b is a cross-sectional view showing a modified embodiment of the structure of FIG. 6a.

FIGS. 1, 5 and 6 illustrate, in a greatly simplified manner, the housing I of a rotary piston engine. This engine comprises two working chambers and, correspondingly, two combustion chambers, also not further identified. The piston 2 has a trochoidal configuration and rotates in the direction of the arrow. The wall of the housing I constitutes the outer envelope curve branches with respect to the trochoidal piston 2. What is involved, therefore, is an engine with a sliding engagement and two contraction points of the housing at which points the radial sealing strips 4 are located. During the rotational movement, the piston center M executes a circle 3 about the central point M In principle, the rotational movement may be produced in any desired manner. Selected in this case is a construction which does not utilize conventional gearing, but an eccentric control instead. Such an eccentric gear is known per se. Provided for the two axial directions 1: and y is one guide ring each 6.1: and 6y, respectively, together with a disc rotatably positioned therein. Coordinated to both discs is an eccentric 5 whose center coincides with the trochoid center M,. The eccentric 5 carries the piston 2 and is non-rotatably connected thereto. The eccentric shaft EW of the engine rotatably extends through the eccentric 5. The two guide rings 6): and 6y are displaceable in the x-direction and in the ydirection together with the discs mounted therein. The displaceability and the slide bars necessary for this purpose are shown in FIG. 1 for the x-direction. The rods at the slide bar are identified with the reference numerals 7 and 7'. Likewise, FIGS. 5a, b and c show slide bars 7y and 7y for the y-direction. By means of this gear arrangement, the piston 2 is caused to rotate in the direc tion of the arrow, and furthermore, the opposite rota tional movement of the eccentric shaft, which has not been shown, is forcibly effected.

The slide bars 7 and 7' of the guide gear are utilized as the pistons of the lubricant pumps 8 and 8'. The mutually corresponding elements of the left and of the right slide bar and pump have been identified in the drawing with the same reference numerals, difi'ering however in the sign. The guide gear with the lubricant pumps 8 and 8' mounted thereon is positioned laterally outside of the lateral housing wall, as illustrated by pump housing sections la and 1b of housing 1 in FIG. 6a, and does not obstruct the piston movement in any way. For this reason, the elements of the guide gear have been shown in dashed and dash-dotted lines. For each of the lubricant pumps 8 and 8' one inflow line 9 and 9' is present. The inflow direction of the lubricant is indicated by an arrow. Feed lines 10 and 10 extend from the lubricant pumps by way of non-return valves 11 to the distributing lines for the lubricant. In the embodiment shown, the lubricant pump 8 conveys the lubricant by way of the feed line 10 to the two distributing lines 12a and 12b which supply in each case, via a non-return valve 11, the running-up or rising side of the radial sealing strips 4 with lubricant. In an analogous manner, the lubricant pump 8' supplies, by way of the distributing line 12a and 12b, equally via non-return valves 11, the running-down or descending sides of the radial sealing strips 4. The non-return valves 11 are positioned in each case closely ahead of the oil grooves of the radial sealing strips 4. The oil grooves themselves have been merely indicated in FIG. 1 in the sealing strip bed. The lubrication of the sealing strip 4 is effected from the oil grooves through the gap 4a for the rising or running-up side, and through the gap 4b for the running-down or descending side. In each end position of the slide bar (for example the slide bar 7, FIG. 1), the rising side of the sealing strips 4 is supplied with lubricant. In the other end position of the slide bar, the descending side of the sealing strip 4 is lubricated. The lubrication of the rising and of the descending sides takes place alternately. It is also possible to lubricate both sides simultaneously.

While the pump housing sections In and lb of FIG. 6a may be replaceably mounted on housing 1, FIG. 6b shows a modified pump P which is mounted in a manner which makes it more readily replaceable. In FIG. 6b, pump P is provided with pump chamber 80 which is in communication with and forms an extension of the chamber of pump 8. Slide bar extension 70 is attached to slide bar 7 and slides in chamber 8c of pump P.

It is shown in FIG. 1 that the running-up or rising sides of all the sealing strips 4 are lubricated simultaneously. It is also possible, however, to effect the lubrication of the individual sealing strips successively. For this purpose, for example, one sealing strip could be lubricated by the slide bar illustrated, coordinated to the guide ring 6x and the pump 8, whereas the other sealing strip 4 could be supplied by an analogously constructed lubricant pump coordinated to the guide ring 6y. It is apparent that other pump types also may be used without difficuity, provided they are guided or controlled by the rotating eccentric shaft. In the case of the guide or control by means of the eccentric shaft, separate control means for the lubricant pumps are eliminated in a simple manner. The construction and provision of the lubricating device described herein is not limited to the use in two-chambered rotary piston engines but is usable, of course, also for rotary piston engines whose construction is based on other trochoids and which have more working chambers.

FIGS. 2a and 2b illustrate in different views and at an enlarged scale the provision of the oil grooves in the sealing strip bed. The radial sealing strip 4 is guided in its sealing strip bed within the housing 1. Disposed at the two lateral flanks of the sealing strip bed are the oil grooves 41 and 42. They extend over the entire length of the radial sealing strip 4 and project to the outside through the lateral housing wall 1'. Positioned immediately ahead of the oil groove 42 is also a non-return valve 11. By way of this non-return valve and the distributing lines, the fine oil groove is in connection with one of the two lubricant pumps 8 or 8', which have not been illustrated in detail here. The delivery or supply of the lubricant to the fine oil grooves 41 and 42, however, also make take place in any other manner. The lubrication proper of the radial sealing strip 4 is effected from the oil groove 41 by way of a narrow gap 40 to the rising side of the sealing strip. The descending side of the sealing strip 4 is supplied with lubricant from the oil groove 42 through a corresponding narrow gap 4b between the housing and the sealing strip.

FIG. 3 illustrates the two end portions of the guide gear with the slide bars 7 and 7'. The lubricant pumps formed therefrom have again been identified with ref erence numerals 8 and 8', as in FIG. I. For the sake of a clearer representation, the guide ring 6x has been omitted. The slide bar 7 is shown here in one end position, and this end position for the lubricating pump 8 corresponds specifically to one dead center (UT) position. The other end position, namely the other dead center (OT) position, has been shown in dash-dotted lines. The entire stroke H between the two positions corresponds to four times the eccentricity of the rotary piston engine, i.e. to four times the distance of the two centers M and M For the feed of the lubricant, the entire stroke H is not absolutely required, but for example, the part h, suffices for the dosage or metering. The dosage results from the arrangement of the inflow line 9. The working stroke h, between the inflow line 9 and the OT position determines the quantity fed. The lubricant is further fed through the line 10 in the direction of the arrow. By a different position of the inflow line, for example 9' in FIG. 3, at a shorter distance k from the cylinder end in the lubricant pump 8', a smaller quantity is fed. Another possibility for metering or dosing the quantity of lubricant is the selection of different cross-sections for the pumps 8 and 8' and for the slide bars 7 and 7'. In this case, the distances h and h of the inflow lines 9 or 9 no longer play the role discussed above.

FIG. 4 illustrates a different arrangement for dosing or metering the lubricant in a longitudinal and crosssectional view thereof. The slide bar of the guide gear again constitutes a piston having an associated cylinder with the connecting feed line 10. The lubricant is conveyed by an inflow line 9 at any desired point within the UT position and distributed through an annular groove 9a ove the circumference of the cylinder. From the annular groove 9a axial grooves 8a extend in the direction toward the end of the lubricant pump 8. These grooves 8a terminate at a distance from the cylinder end, and from the OT position, which corresponds to the effective working stroke h or 11 During the piston move merit of the slide bar 7, from the UT position to the closing-off of the inflow lines 9 or 9' in FIG. 3, or to the closing-off of the grooves 80 in FIG. 4 by the piston, the lubricant is again forced back through the inflow line 9. Only that part of the lubricant which has collected in the pumps after the closing-off of the inflow lines 9 or the grooves 8a in the area h or 11 is conveyed via the line for the lubrication proper.

With the embodiment shown and described. the possibilities for the pump construction and the dosage or metering of the amount of lubricant are by no means exhausted. The most diversified changes and modifications can be made without difficulty. [t is readily feasible and possible that one skilled in the art may choose, instead of the two fixed settings disclosed herein for the dosage of lubricant, a construction in which the quantity delivered can be regulated, if necessary, also be displacing a structural element.

It will be obvious to those skilled in the art that many modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.

What is claimed is:

l. in a rotary piston engine having a piston means of epitrochoidal configuration, a housing having an internal configuration conforming substantially to the outer envelope curve of the trochoid, eccentric shaft means operatively connected to said piston, radial sealing strip means mounted in a corresponding bed in the interior side walls of said housing and lubricant groove means formed in the walls of said bed, the improvement comprising, drive means operatively connected to said piston to convert linear sliding movement of said drive means to rotary motion of said piston, pump means operatively coupled to at least one sliding element of said drive means, lubricant line means operatively connecting said pump means to said lubricant groove and nonreturn valve means operatively mounted in said lubricant line.

2. An engine in accordance with claim 1 wherein the sliding element of the drive means forms a part of the pump.

3. An engine in accordance with claim 1 wherein the sliding element of the drive means is operatively connected to the pump and drives said pump.

4. An engine in accordance with claim 1 which includes means for supplying an increased quantity of lubricant to the lubricant groove on the running-up side of the sealing strip.

5. An engine in accordance with claim 1 wherein the lubricant line means passes through the side wall of the housing of said engine and thence to the lubricant groove means.

6. An engine in accordance with claim 1 wherein the lubricant line means includes a pair of lubricant line means, one of which is connected to the lubricant groove means in the bed on one side of the sealing strip means and the other of which is connected to the lubricant groove means in said bed on the other side of said sealing strip and said pump means alternately supplies lubricant to said lubricant groove on said one side of said sealing strip through said one lubricant line means and to said lubricant groove on said other side of said sealing strip through said other lubricant line means.

7. An engine in accordance with claim I wherein a plurality of sealing strips are provided. the lubricant line means includes a pair of lubricant line means, one of which is connected to all lubricant groove means in the beds on the running-up sides of said sealing strips and the other of which is connected to all lubricant groove means in said beds on the running-down sides of said sealing strip means and said pump means alternately supplies lubricant to said lubricant grooves on said running-up side of said sealing strips through said one lubricant line means and to said lubricant grooves on said running-down side of said sealing strips through said other lubricant line means.

8. An engine in accordance with claim 1 wherein the lubricant line means includes a pair of lubricant line means, one of which is connected to the lubricant groove means in the bed on the running-up side of the sealing strip and the other of which is connected to the lubricant groove means in said bed on the runningdown side of said sealing strip, and the pump means includes a pair of pump means, one of which is connected to the lubricant line means leading to said running-up side of said sealing strip and the other of which is connected to the lubricant line means leading to said running-down side of said sealing strip.

9. An engine in accordance with claim 1 wherein the pump means includes a pair of pumps, a pair of input lubricant line means is provided, one of which is connected to one of said pumps and the other of which is connected to the other of said pumps, and said input lubricant line means are connected to said pumps at different distances from the dead-center position of the pistons of said pumps, whereby the lubricant output of said pumps differs.

10. An engine in accordance with claim 1 wherein the pump means includes a pair of pumps, axially extending grooves are provided in the walls of each of said pumps, a pair of input lubricant line means is provided, one of which terminates in said grooves in said wall of one of said pumps and the other of which terminates in said grooves in said wall of the other of said pumps, and said grooves in said walls of each of said two pumps terminate at different distances from the dead-center position of the piston of the respective pumps, whereby the lubricant output of said pumps differs. 

1. In a rotary piston engine having a piston means of epitrochoidal configuration, a housing having an internal configuration conforming substantially to the outer envelope curve of the trochoid, eccentric shaft means operatively connected to said piston, radial sealing strip means mounted in a corresponding bed in the interior side walls of said housing and lubricant groove means formed in the walls of said bed, the improvement comprising, drive means operatively connected to said piston to convert linear sliding movement of said drive means to rotary motion of said piston, pump means operatively coupled to at least one sliding element of said drive means, lubricant line means operatively connecting said pump means to said lubricant groove and non-return valve means operatively mounted in said lubricant line.
 2. An engine in accordance with claim 1 wherein the sliding element of the drive means forms a part of the pump.
 3. An engine in accordance with claim 1 wherein the sliding element of the drive means is operatively connected to the pump and drives said pump.
 4. An engine in accordance with claim 1 which includes means for supplying an increased quantity of lubricant to the lubricant groove on the running-up side of the sealing strip.
 5. An engine in accordance with claim 1 wherein the lubricant line means passes through the side wall of the housing of said engine and thence to the lubricant groove means.
 6. An engine in accordance with claim 1 wherein the lubricant line means includes a pair of lubricant line means, one of which is connected to the lubricant groove means in the bed on one side of the sealing strip means and the other of which is connected to the lubricant groove means in said bed on the other side of said sealing strip and said pump means alternately supplies lubricant to said lubricant groove on said one side of said sealing strip through said one lubricant line means and to said lubricant groove on said other side of said sealing strip through said other lubricant line means.
 7. An engine in accordance with claim 1 wherein a plurality of sealing strips are provided, the lubricant line means includes a pair of lubricant line means, one of which is connected to all lubricant groove means in the beds on the running-up sides of said sealing strips and the other of which is connected to all lubricant groove means in said beds on the running-down sides of said sealing strip means and said pump means alternately supplies lubricant to said lubricant grooves on said running-up side of said sealing strips through said one lubricant line means and to said lubricant grooves on said running-down side of said sealing strips through said other lubricant line means.
 8. An engine in accordance with claim 1 wherein the lubricant line means includes a pair of lubricant line means, one of which is connected to the lubricant groove means in the bed on the running-up side of the sealing strip and the other of which is connected to the lubricant groove means in said bed on the running-down sidE of said sealing strip, and the pump means includes a pair of pump means, one of which is connected to the lubricant line means leading to said running-up side of said sealing strip and the other of which is connected to the lubricant line means leading to said running-down side of said sealing strip.
 9. An engine in accordance with claim 1 wherein the pump means includes a pair of pumps, a pair of input lubricant line means is provided, one of which is connected to one of said pumps and the other of which is connected to the other of said pumps, and said input lubricant line means are connected to said pumps at different distances from the dead-center position of the pistons of said pumps, whereby the lubricant output of said pumps differs.
 10. An engine in accordance with claim 1 wherein the pump means includes a pair of pumps, axially extending grooves are provided in the walls of each of said pumps, a pair of input lubricant line means is provided, one of which terminates in said grooves in said wall of one of said pumps and the other of which terminates in said grooves in said wall of the other of said pumps, and said grooves in said walls of each of said two pumps terminate at different distances from the dead-center position of the piston of the respective pumps, whereby the lubricant output of said pumps differs. 